Automatic cutoff switch for typewriters



July 8, 1952 .1 F. sMATHERs AUTOMATIC CUTOFF SWITCH FOR TYPETRITERS Filed June 16, 1949 s n m m. nu mm E N O: lkl :.:ifn M uw m www m NQ ww ww Nm, h .0 o u. m* 1 u E QP Nw km S ...#...mrdW- ATTORNEY Patented July 8, 1.7952

AUTOMATIC oUToFF SWITCH For. f TYPEWRITERS James F. Smathers, Poughkeepsie, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application June 16, 1949, Serial No.'99,465

4 Claims. l t

This invention relates to typewriting machines.

The invention is primarily concerned with improving power operated typewriting machines to the extent of providing means for reducing to a minimum the power loss arising from leaving the machine unattended for appreciable lengths of time without placing the main switch in the "oif position.

An object is to provide a timing device which will automatically stop the driving motor of the typewriter if the typist goes away and leaves the machine unattended for longer than predetermined'lengths of time.

An object is to provide an automatic cut-out device for power operated typewriting machines which is simple and reliable in its operation, and which does not interfere with the normal use of the machine. i

An object is to provide an automatic cut-out device which is automatically disabled as soon as the operator resumes use of the machine after leaving the machine unattended or failing to operate it for a period less than the cut-off period.

Other objects of the invention will be pointed out in the following description and claims 'and illustrated in the accompanying drawings,l which disclose, by way ofexamplathe principle of the invention and the best mode, which has been ccntemplatedmf applying that principle.

In the drawings:

Fig. 1 is a vertical section of a typewriting machine incorporating the present invention.

Fig. 2 is a plan view of the cut-off mechanism.

Fig. 3 is a 'vertical section on the line 3 3 of Fig. 2. o

Fig. l illustrates the keyboard and power operating mechanism of a well-known form of power operated typewriter. It will be understood, however, that the invention is not limited to this particular form of typewriter, but may be used in anypower operated typewriter with suitable modications Ynot affecting the principle of the invention.

The power operated typewriter includes a typical type bar I pivotally mounted on the fulcrum wire II which is usually carried by some form of segment mounted for case shifting operation to select either of the twov types Illa on the type bar I0. The type bars are operated by power mechanism controlled by the character keys I2 which control cam units I3 in a wellknown way to render the cam units operative by the power roller I4, shown in outline form by dotdash lines. Each cam unit is pivotally mounted on one of two pivot Wires I3a and is connected by a link I5 to a sub-lever I6 pivoted on a fulcrum wire Il suitably mounted in the framework of the machine. The type bars I0 are connectedl to the sub-levers I 6 bymeans of links I8 and toggles I0b.

The depression of a character key I2 renders the cam units I3 operative in a well-known way by the power roller I4, resulting in the links I5 being drawn downwardly and rocking the sublever I6 counterclockwise thereby drawing the link I8 to the left and actuating the type bar I0 to printing position.

The space bar or key I8 controls a'cam unit I3b similar to the cam units I3 and this cam unit I3b is connected by a link I5aI to a lever IBa also pivoted on the wire I'I.' Through a link connection Ia between the lever IIa and the usual carriage escapement mechanism (not shown), the cam unit I3a operates the escapement mechanism to space the platen carriage (not shown) each time the space bar I9 is depressed. The use of the space bar in the normal operation of the machine is utilized in the present instance as a means of disabling the automatic cut-off mecha'- nism.

The cut-off mechanism consists of a unit suitably mounted in the main framework of thema* chine and includesthe U-shaped frame 20 to which is secured the `plate 2I to form a'boxshaped housing for the timing mechanism. `The timing mechanism includes a first ratchet 22 which is loose on a short stud 23 carried bythe U-shaped frame 20 and the plate 2|. Mounted alongside the ratchet 22 is a second ratchet 24 also loose on the stud 23. Fixed tothe side of the ratchet 22 confronting the ratchet 24 is an eccentric cam 22a rotatable within an oval opening 25a in a lever 25 pivoted on the stud 26 carried by the frame 2IJ. As a result of this construction, the lever 25 is oscillated on the -stud 2B once for each revolution of the ratchet 22.

Pivotally mounted on the free end of the lever 25 is the pawl 21 which is urged into engagement with the teeth of the ratchet 24 by a spring 28. The throw of-.the eccentric22a is such that the ratchet 24 will be advanced one tooth space for each full revolution ofthe ratchet 22 and thus constitutes areduction gearing causing the ratchet 24 to travel at a relatively.y slow rate compared to the ratchet 22. The latter is actuated by an arm 29 pivoted on the stud 23 and carrying a pawl 30 engaged with the ratchet 2.2 by a spring 3I anchored to the tail of the pawl 30 and to the frame 2B. This spring also helps to restore the arm 29'. The arm 29 is connected tion and the cam 34 is proportioned so that the racket 22 will be advanced one tooth-space for'` each revolution of the power roller I4.

Fixed to the side of the ratchet 24 is a pinion 24a which acts as one member of a clutch, the other member consisting of a pinion 35 loose on the stud. 23 and cut so that its teeth extend beyond the body of the pinion 35 into the tooth spaces of the pinion 24a. The pinion 35 has a circumferential groove 35a engaged by one arm of a shift lever 36 pivoted at 31 on a lug formed in the plate 2|. When the lever 36 is actuated in a counterclockwise direction (Fig. l) the projecting ends of the teeth 'of pinion 35 'become disengaged 'from the v-pinion ,24a and permit the pinion 35 to run free of the ratchet 24.

The pinion 35 constantly meshes with a rack 38 which is suitably guided in the frame 20 and normally urged to the Vleft by a spring 39 anchored to a pin carried by the right-hand end of the rack 38. The plate 2I is provided with an extension having an adjusting screw 2lb which may be used to regulate the length of the cut-oil cycle. When the lever 33 is actuated as aforesaid, the pinion 35 is freed from the ratchet 24a permitting the spring 33 to draw the rack to the left until it engages the screw 2 ib. Normally the spring 43 holds 'the lever 33 in the position of Fig. 2, maintaining clutch engagement between the pinion 24a and the pinion 35, whereby the rack 38 will be progressively advanced to the right (Figs. l and 2) as long as the machine is in operation.

The vlever 36 has a link connection 4I to the lever IBa which rocks counterclcckwise in Fig. l each time the space bar or key |19 is operated. This causes the link 4I to be thrust to the right thereby disengaging the pinion 35 from the l pinion 24a. Thus, during 'the course of normal operation of the machine, the rack 33 will never be advanced more than a few tooth-spaces to the right before it will be withdrawn by the spring 39 to starting position in contact with the stop screw `2 Ib'.

If the machine is left unattended for longer than a predetermined length of time, however, the rack 33 will continue to advance to the right to the limit of its travel and at that point will actuate the motor switch to stop the driving motor Yfor the machine. This is effected by a lugor pin 38a -projecting from the side vof the rack 38 in a position to engage a pin 42 carried by the arm 43 of a toggle switch 44. The pin Y33 is connectedby a link l4&5 with the manual switch lever 46 and also is connected by a link 47 with the lever 36. The drawings show the switch in the on position with the motor running and under theseV Vconditions the engagement of the pin 38a with the pin 42 will result in actuating the switch lever 43 to the right or counterclock- 'wise in Fig. 2, to the oii position, thereby in- 4 44 to the on position. This link also releases the rack when the switch is turned 01T manually.

lt is apparent from the foregoing description that if the machine is left unattended, the rack 138" will be progressively advanced to; the right and afteratime delay dependent upon the reduction eifected through the ratchets 22, 24 and the pinion 33, switch 44 will be actuated to the off position automatically and stop the machine. However, if the Aoperator resumes operation of the machine while the cut-off cycle is in progress, the

pinion 35 will be disengaged from the pinion 24a and restart the timing cycle each time the space bar is operated. This, on the average, will take place approximately every five character key operations in normal typing. l

The reduction is designed so that the timing cycle is long enough to permit a short interruption by the typist, such as a telephone conversation of vshort duration, without shutting ofi the motor, but is short enough so thatif the'stenog rapheris called away on an errand and forgets to turn off the switch, the machine will be stopped within a minute or twojthe length of thecut-oi cycle depending upon the number of teeth in the ratchets 2'2, `24, the pitch diameter of pinion 35, and the adjustment of the screw 2 Ib. This `cycle may be adjusted to suit the conditions under which thema-'chinois used. If desired, the adjusting screw 2lb may be omitted Yand the rack 38 may/be stopped in a xed position as, for example, by the part 33h thereof engaging the side of the frame 20. f f v n While there 'have been shown and described and pointed out the fundamental novel features ofthe invention, as applied'to a preferred embodiment, it will be understood that various omissions and substitutions and changes inthe form and details of the device illustrated and in its operation :may be made by those skilled in the art without departing from the spirit of the invention. It is the intention, therefore, to be limited only as'indicated by the scope of the following claims.

What i's .claimed Vis "1. Ina typ'ewrting machine, .a power actuator, a power' unit, la manual device for coupling the power unit to Vsaid power'actuator, a 4main switch for stopping said actuator, a member movable from a starting position to a position for operating said switch; va reduction gear enabling said actuatort-o drive'said member ata reduced Vspeed 'from said starting position to said switch operating position, including a rstratchet and pawl device actuated by vsaid actuator and a second ratchet and pawl device actuated by the first ratchet and pawl device and actuating said member; a clutch connecting said second ratchet and pawl device to said member and vreleased by an operation `of said power unit, and means to restore said member to starting position when said clutch is released.

2. Zin-combination with a power operated typewriter having a main power actuator, a switch for controlling the actuatoig'and a manually controlled lpower device actuated by the main actuator; a switch operating member having a stroke from a closed switch position to a position in which said switch is actuated to open position, means operated by said actuator for driving said member to open switch position at a definite time rate, meansvcontrolled by thepower devicev for disabling theldrivingmeans and restoringsaid member -to closed-switch position, and a manual device for opening said switch and operating the disabling means.

3. In a typewriting machine, a device to be operated, a main power operator, a manual device for connecting said rst device to the'power operator for operation by the'latter, a main switch for controlling the main operator, a timing device actuated by said main operator and having means to operate said switch after a predetermined period of time to stop said main operator, means controlled by said manual device for disabling said timing device each time said manual device is operated, and a connection from said switch to said disabling means to temporarily disable the timing device when the switch is opened.

4. In a typewriting machine, a power actuator, a power unit, a manual device for coupling the power unit to said power actuator, a main switch for stopping said actuator, a timing device including an element actuated by said actuator toward a position in which said switch is opened to stop operation of said power actuator and including a clutchrreleased by the power unit for disabling said element to prevent operating said switch, and a clutch releasing connection between the switch and the clutch to restart the timing cycle each time the switch is opened. v

JAMES 1E'. SMATHERS.

REFERENCES CITED The following references are of record in the le of this patent: i

UNITED STATES PTENTS` Number Name Date 1,549,101 Wales Aug. 11,1925 1,557,457 Hawley Oct. 13, 1925 1,667,773 Degener May 1, 1928 

